The objective of the proposed research is to develop a series of fluorescent stains suitable for the simultaneous multiple staining of cytological specimens in flow systems. While these stains are intended primarily for use in automated cancer screening and detection, their usefulness extends to any area of cytology where multiple fluorescent labeling might be advantageous. The key features of these novel stains are high fluorescence intensity and extremely narrow emission bands. Also, the stains must exhibit a high chemical stability and a fluorescence lifetime compatible with the constraints of the flow system employed. To achieve these diverse features, we plan to design and synthesize a series of rigid cage-like polychelate complexes containing a trivalent lanthanide--specifically, europium, terbium, samarium, or dysprosium as the light-emitting center. These chelates will be coupled to proteins through a suitable functional group, and the fluorescence as well as the stability of the protein-bound chelates will be investigated to assess the factors which favor permanent and effective staining. The proposed research essentially most involves the application of the current knowledge and methods in inorganic coordination chemistry, molecular spectroscopy, and organic synthesis to the development of a new tool for cytological investigations.